scoping MAF-MAP on late diesels

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scoping MAF-MAP on late diesels

Postby sapper826 » Mon May 24, 2010 7:27 pm

Hi! all, tried scoping MAF/MAP on 08 Astra D, and Fiat Punto 07 13 JTD. The waveforms are all like 0v-5v hall effect, and only get closer together on snap throttle, any way of testing them?
TIA
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Re: scoping MAF-MAP on late diesels

Postby Matt Fanslow » Mon May 24, 2010 8:00 pm

For one, it is difficult to analyze a pulse-train such as what you are describing with the MAF and MAP sensors. Scoping the pulse-train will allow you to monitor the signal integrity and watch for catastrophic signal breakdowns.

PicoScope 6 (6.4.28) with a 4000 series DSO will allow you to look at Frequency up to 20kHz. I don't know the operating range of the sensors you speak, so this may or may not allow you to test to the upper limit of the sensor. Graphing frequency, however, would lend itself better to testing for a skewed sensor.

HTH. Later, Matt.
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Re: scoping MAF-MAP on late diesels

Postby Guest » Mon May 24, 2010 8:44 pm

[quote="Matt Fanslow"]For one, it is difficult to analyze a pulse-train such as what you are describing with the MAF and MAP sensors. Scoping the pulse-train will allow you to monitor the signal integrity and watch for catastrophic signal breakdowns.

PicoScope 6 (6.4.28) with a 4000 series DSO will allow you to look at Frequency up to 20kHz. I don't know the operating range of the sensors you speak, so this may or may not allow you to test to the upper limit of the sensor. Graphing frequency, however, would lend itself better to testing for a skewed sensor.

HTH. Later, Matt.[/quote]

thanks for your reply, will work on the graphing.
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Re: scoping MAF-MAP on late diesels

Postby Dave Hill » Sat May 29, 2010 3:17 pm

Hi Matt

I don't know which version of pico software that I am running, but I think I can only have a 2khz frequency range. Has this been increased to 20khz, or is that a typo?

Ordinarily I could check to see, but with only an iPhone to connect to the net, I am a bit limited. :?

I really hope that the Pico crew have increased the range, as it will be very useful.

Regards

Dave
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Re: scoping MAF-MAP on late diesels

Postby mapengo » Sun May 30, 2010 7:05 am

Matt Fanslow wrote:For one, it is difficult to analyze a pulse-train such as what you are describing with the MAF and MAP sensors. Scoping the pulse-train will allow you to monitor the signal integrity and watch for catastrophic signal breakdowns.

PicoScope 6 (6.4.28) with a 4000 series DSO will allow you to look at Frequency up to 20kHz. I don't know the operating range of the sensors you speak, so this may or may not allow you to test to the upper limit of the sensor. Graphing frequency, however, would lend itself better to testing for a skewed sensor.

HTH. Later, Matt.


Hi Matt,

Are you saying that we can now graph the frequency from a digital MAF?
Enabling us to see a conventional MAF waveform shape with the "gulp" from a digital MAF.
If so can you post a screen capture with settings please?

Cheers

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Re: scoping MAF-MAP on late diesels

Postby Matt Fanslow » Tue Jun 01, 2010 5:00 pm

My apologies for the delay. Here is a capture


Image

Later, Matt.
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Re: scoping MAF-MAP on late diesels

Postby mapengo » Tue Jun 01, 2010 5:21 pm

Many thanks Matt,

Cheers

Doc...
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Re: scoping MAF-MAP on late diesels

Postby Matt Fanslow » Tue Jun 01, 2010 6:27 pm

I've received some comments about the spikes on the frequency graph. I've taken a second capture with a greater number of requested samples and loaded it here: http://www.wavehook.com/dbase/bigpic.ht ... d=1599.gif. You can download the .psdata from there and manipulate it as you please.
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Re: scoping MAF-MAP on late diesels

Postby mapengo » Tue Jun 01, 2010 7:58 pm

Nice one Matt 8) ,

Appreciated

doc...
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Re: scoping MAF-MAP on late diesels

Postby Alan » Mon Jun 07, 2010 8:03 am

Matt,

Thanks for the post and comments about the spikes.

The 0 to 20kHz range is there to allow the scoping of "digital" MAF sensors but its a bit of a work in progress at the moment.

The spikes are due to it being very sensitive to noise. We have this sorted in a alpha version of the software but you will need to be patient before you can have a copy!

I will put together some notes on this an post later.

Regards
Alan
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